The invention relates to a layer construction with an organic layer and a further transparent layer which covers the organic layer and is harder than the organic layer. The invention also relates to a process for producing this layer construction comprising an organic layer and a cover layer which covers the organic layer and which is harder than the organic layer in which the organic layer to be covered with the cover layer first is cleaned and then the cover layer is deposited by chemical vapor deposition on the surface of the organic layer from a precursor material present in the gas phase.
Kuehnle et al., U.S. Pat. No. 5,211,995 discloses a process for covering organic surfaces with a layer which is harder than the organic layer. In this process, a cover layer formed preferably of titanium nitride (TiN.sub.2) or silicon nitride (Si.sub.3 N.sub.4) is applied by means of a CVD (Chemical Vapor Deposition) process on top of an organic layer which, for example, may be a clear finish lacquer of a sheet of metal painted with colored lacquer. For this purpose, the painted sheet metal is cleaned, introduced into a reactor, the reactor is evacuated, a gas comprising a precursor--hereinafter referred to as precursor material--is introduced and the precursor material is energetically excited. When process parameters are appropriately adjusted, the cover layer then deposits on the surface of the organic layer, i.e. on the clear lacquer. A layer construction of this type, however, exhibits a surface with an optically irregular appearance, so that it cannot be used to produce high value products. Also the durability of the cover layer toward chemical and mechanical influences is less than the theoretically expected values.